Such melters for processing substantially solid, free-flowing adhesive particulate and supplying liquefied adhesive, especially hot melt adhesive, are especially used in industrial applications. Adhesive is generally provided in an initially solid form, for example in the form of particles or pellets or in a block or the like, and then liquefied with the aid of the melter. Solid adhesive pellets or adhesive particles may be provided in solid, free-flowing and therefore pourable form in sacks or other containers, supplied to the melter by means of a filling device and liquefied. The adhesive liquefied with the aid of the heating device of the melter may be conveyed by means of the pump through a hose to a consumer, for example an application device for dispensing and applying the adhesive onto a substrate. For example, the application device may be an application head having a slit nozzle for planar application, or a device for application of one or more beads, or a spray application device, or a manual spray gun.
Depending on the current demand of one or more consumers, the adhesive is liquefied in a specific quantity by means of the heating device. The demand is thereby regularly subjected to strong fluctuations. There may be periods in which the demand is strongly reduced or even interrupted. The melting process, the heating device and the heat and temperature development in the tank in which the adhesive may be present in part in a solid, semisolid or even already liquefied form are subject to an inertia. For example, if the demand on the part of the consumer is interrupted and therefore liquefied adhesive is no longer dispensed from the melter, an elevated, slowly decreasing temperature and thermal energy initially remain in the heating device, in the tank and in the partially liquefied, partially semi-liquefied or still solid adhesive. This thermal energy spreads over time into the adjacent surroundings and especially also into the filling device coupled with the melter, said filling device being for filling the tank with solid adhesive particles. Such a filling device is often and normally arranged above the tank. Heated gases, especially heated air located in the tank, rise upward due to free convection and may arrive in the filling passageway of the filling device through the inlet opening of the tank.
Such a heat input from the area of the tank into the filling device is disadvantageous because, on the one hand, thermal energy is thereby lost from the tank, which increases the power consumption; and, on the other hand, the thermal energy introduced into the filling device can convert adhesive particles located there from the solid state into the liquid or semi-liquid state. This may lead to unwanted effects, for example adhesion of the filling device and, in some circumstances, interruption of the operation of the filling device.